Metal Slug 4 & 5 Hints for PlayStation 2
When playing as snake in the tanker go to the lockers with women on them go to the one with the women in the bikini.
Open the locker don't close it flaten yourself on her then equip a gun and tap on her if it was done right you should here a weird noise.
Bend down and touch her while moving acroos the locker bent down and you should go into alert mode. Try it it's funny.